Vibration

[TFENT]

So I have a 90 ZR1 with 31,000 on the odometer, totally stock except for a Marc H. chip. Also live in San Diego where we can open up the cars more then most people (ie 100+) on the freeways. So I took out the vette for a "Sunday" cruise this weekend (150 miles). The car has always had the Corvette creaks and rattles but anytime I am over 60mph there is a vibration that is irritating my beyond belief. The car has new tires and rims and I have had them checked like 4-5 times on a load match machine. They are perfect. Thing is this is my first Vette. I do not know if these cars have a natural tendency to have a high speed buzz or not. Since It was sitting a very long time in storage before I got it I am wondering if maybe the drives shaft(s) or U-Joints are bad/frozen or out of balance.

The buzz is just enough to cause the rearview mirror to vibrate enough to not see out of it. Its not real bad like a flat spot. Just as i stated earlier it's an irritating buzz. especially at 110 when I NEED the rearview mirror.

TIA for any suggestions.

[tccrab]

Could be U joints, but with only 31k miles they *should* be just getting broken in not worn out.
Has the transmission been out of the car recently?
When this vibration happens, can you feel it through the shifter?
Does the shifter lift under heavy acceleration?
If so, try tightening the C-Beam bolts, and if you don't already have them, order up a set of Bill Boudreau's (The ZF Doc) C-Beam plates.

My '90 is noisy at 100+ :mrgreen: but no vibrations like you describe.

TomC
'Crabs

[TFENT]

Could be U joints, but with only 31k miles they *should* be just getting broken in not worn out.
Has the transmission been out of the car recently?
When this vibration happens, can you feel it through the shifter?
Does the shifter lift under heavy acceleration?
If so, try tightening the C-Beam bolts, and if you don't already have them, order up a set of Bill Boudreau's (The ZF Doc) C-Beam plates.

My '90 is noisy at 100+ :mrgreen: but no vibrations like you describe.

TomC
'Crabs

Tranny has never been removed.

Little to no vibrations through the shifter

Shifter does not move under acceleration.

I will get a set of the C-beam plates. :)

Thanks Tom ;)

[ZZZZZR1]

So I have a 90 ZR1 with 31,000 on the odometer, totally stock except for a Marc H. chip. Also live in San Diego where we can open up the cars more then most people (ie 100+) on the freeways. So I took out the vette for a "Sunday" cruise this weekend (150 miles). The car has always had the Corvette creaks and rattles but anytime I am over 60mph there is a vibration that is irritating my beyond belief. The car has new tires and rims and I have had them checked like 4-5 times on a load match machine. They are perfect. Thing is this is my first Vette. I do not know if these cars have a natural tendency to have a high speed buzz or not. Since It was sitting a very long time in storage before I got it I am wondering if maybe the drives shaft(s) or U-Joints are bad/frozen or out of balance.

The buzz is just enough to cause the rearview mirror to vibrate enough to not see out of it. Its not real bad like a flat spot. Just as i stated earlier it's an irritating buzz. especially at 110 when I NEED the rearview mirror.

TIA for any suggestions.

I agree with C beam plates, but...

What kind of wheels (OEM)? What kind of tires?

One thing that I have heard is to get them Road Balanced (not just the standard balancing).

[TFENT]

I agree with C beam plates, but...

What kind of wheels (OEM)? What kind of tires?

One thing that I have heard is to get them Road Balanced (not just the standard balancing).

A Mold Factory wheels w/ Nitto 555's (brand new)

I got them load matched or road balanced

[jonszr1]

you might want to jack up the rear of the car and ck your 1/2 shafts and your rear bearings as well as the bushings in the rear. sometime when a car sits for a long while things can start to go bad from lack of use

[TFENT]

you might want to jack up the rear of the car and ck your 1/2 shafts and your rear bearings as well as the bushings in the rear. sometime when a car sits for a long while things can start to go bad from lack of use

The u-joints in the 1/2 shafts? What bushings?

[tomtom72]

Not trying to be a wise a$$.....but what setting on the FX3 are you using?

I ask because on setting 3 ( performance? ) setting my rear view along with the side mirrors are useless after about 130. This used to happen in the #2 ( sport? ) setting with the original shocks, and at #3 my eyeballs were vibrating. Okay the roads are proly better where you are....but just saying that the firmer the FX3 setting the more and sooner my mirrors bounce into uselessness.

The only thing with my experience is that I don't hear anything, it's just the chassis transmitting the road conditions, mostly bad, thru the rest of the car. It's enough to make you want to slow down.

:cheers:
Tom

[TFENT]

Not trying to be a wise a$$.....but what setting on the FX3 are you using?

I ask because on setting 3 ( performance? ) setting my rear view along with the side mirrors are useless after about 130. This used to happen in the #2 ( sport? ) setting with the original shocks, and at #3 my eyeballs were vibrating. Okay the roads are proly better where you are....but just saying that the firmer the FX3 setting the more and sooner my mirrors bounce into uselessness.

The only thing with my experience is that I don't hear anything, it's just the chassis transmitting the road conditions, mostly bad, thru the rest of the car. It's enough to make you want to slow down.

:cheers:
Tom

I have a few cars in my inventory as a test bed. I checked on a few roads some as new as 6 months and as smooth as a babies butt. One of my other rides has the same tires, smooth well past 130...It's the car for sure.

Settings either in the middle or the perf setting.

AND I will add I appreciate ANY and all assistance. You guys on this forum are awesome and I thank you for it.

[rhipsher]

Is the vibration coming from the rear. In other words if you reach behind you and put your hand on the rear where your two little compartments are can you feel it or is it coming through the sterring wheel?

[TFENT]

Is the vibration coming from the rear. In other words if you reach behind you and put your hand on the rear where your two little compartments are can you feel it or is it coming through the sterring wheel?

That's a hard question to answer. Here is why. The car sits for long periods of time. It is equipped the Nitto 555's. That means when i do take it out for a drive the tires are flat spotted. I have to warn them up so there is a vibration in the front end until the tires warm up which doesn't take very long but its still there. After 15 mins it calms down quite a bit. I am taking it out for a long drive on Saturday and will be more sensitive when I do. I will check the rear area and report back.

[TFENT]

OK, Took it out for a nice LONG ride yesterday. Total about 225 miles. San Diego to LA and back. Speeds from bumper to bumper then a few races with an M5, Up to 125. I can feel most of the vibration in the rear and the shifter is buzzy. But not all the time. It was vibrating at 75-85 then above 90 it would smooth out. This is weird. I put it into neutral sometimes and it calms down. Under acceleration it get more pronounced. I do not think its a tire or tires. I think its the drivetrain, something in the drivetrain.

[rhipsher]

I'll bet my money it's a bad U-joint or two. If I were you I'd replace them all.

[4DSZR1]

I'll bet my money it's a bad U-joint or two. If I were you I'd replace them all.

I don't want to derail the thread, just a quick question, are all six U-joints the same size?

Thanks
Rick

[Jagdpanzer]

Here is the info posted at Denny's Driveshafts for the C4 Corvette:

http://www.dennysdriveshaft.com/p423_corvette_aluminum_driveshaft__aluminum_half_s haft_rebuild_ki.html

Half Shafts use four Spicer 1350 series U-joints which measure 3.625 inches wide in both directions and 1.187 inch diameter on all bearing caps.

Main drive shaft uses two Spicer 1310 series U-joints which measure 3.219 inches wide in both directions and 1.0625 inch diameter on all bearing caps.
http://www.dennysdriveshaft.com/img/products/1225038377_CorvetteAluminumDriveshaftAluminumHalfS haftRebuildKit.jpg

[jonszr1]

that u joint deal from dennys is a quality deal with the best u joints and straps around .

[4DSZR1]

Great info..... I love this place


Thanks

[FULLPWR]

Tom, did you figure out what it was?
I just put the tranny back in saturday, and its only this morning i notice the same exact thing you described. I did not pay attention to the position of the driveshaft as to the dif yoke when i took it apart a month ago, but the shaft did have a distinctive black mark on the side where the shaft weights are and the yoke had a orange mark, so i put it in "black Opposite Orange" unsure why the yoke didnt have the yellow mark as the manual states though..?? i havent driven it in four years and i really dont remember it having that vibration, my gut memory thinks it didnt... its real noticeable as excactly as you described it.
I think im gonna reposition it 180 like Rick did.

Luis

[TFENT]

Tom, did you figure out what it was?
I just put the tranny back in saturday, and its only this morning i notice the same exact thing you described. I did not pay attention to the position of the driveshaft as to the dif yoke when i took it apart a month ago, but the shaft did have a distinctive black mark on the side where the shaft weights are and the yoke had a orange mark, so i put it in "black Opposite Orange" unsure why the yoke didnt have the yellow mark as the manual states though..?? i havent driven it in four years and i really dont remember it having that vibration, my gut memory thinks it didnt... its real noticeable as excactly as you described it.
I think im gonna reposition it 180 like Rick did.

Luis

Luis:

No i haven't. I only drove it on Saturday. I will get these new u-joints all together this week or so and get them changed out.